Parasocial interaction (PSI) refers to a kind of psychological relationship experienced by an audience in their mediated encounters with performers in the mass media, particularly on television and on online platforms. Viewers or listeners come to consider media personalities as friends, despite having no or limited interactions with them. PSI is described as an illusory experience, such that media audiences interact with personas as if they are engaged in a reciprocal relationship with them. The term was coined by Donald Horton and Richard Wohl in 1956.

Influencer marketing is a form of social media marketing involving endorsements and product placement from influencers, people and organizations who have a purported expert level of knowledge or social influence in their field. Influencers are someone with the power to affect the buying habits or quantifiable actions of others by uploading some form of original—often sponsored—content to social media platforms like Instagram, YouTube, Snapchat, TikTok or other online channels. Influencer marketing is when a brand enrolls influencers who have an established credibility and audience on social media platforms to discuss or mention the brand in a social media post. Influencer content may be framed as testimonial advertising.